The sun is sending increased activity to Earth, potentially causing strong aurora displays this weekend. NOAA forecasts a “strong” geomagnetic storm, rated 3 out of 5, expected late Saturday into Sunday. Auroras, visible as far south as Illinois and Oregon, result from solar particles disturbing Earth’s magnetic field. The storm follows a major solar flare, the largest since 2017, which caused radio blackouts. While timing is fairly certain, intensity predictions remain uncertain. Solar activity can also disrupt satellites and power systems.